Control apparatus for tuning radio receivers



CONTROL APPARATUS FOR TUNING RADIO RECEIVERS Filed April 24, 1944 A; w.PLENSL'ER FIGZ 3 Sheets-Sheet 1 2o 2o 20 d INVENTOR.

ALEXANDER W. PLENSLER wwg v Mrm.

ATTORNEYS Dec. 31, 1946. w, PLENSLER 2,413,515

CONTROL APPARATUS FOR TUNING RADIO RECEIVERS Filed April 24, 1944 3Sheets-Sheet 2 47 INVENTOR ALEXANDER W. PLENSLER dizz M AM ATTORNEYSDec. 31, 1946. A. w. PLENSLER CONTROL APPARATUS FOR TUNING RADIORECEIVERS 3 Sheets-Sheet 3 Filed April 24, 1944 R E & 0 mm H TH M mw mmm M m D N A X E L I A B 8 (\J 8 mm o IO 1 wm QQNI.\/ QDN *8 PatentedDec. 31, 1946 CONTROL APPARATUS FOR TUNING I RADIO RECEIVERS AlexanderW. Plensler, Chicago, Ill., assignor, by

mesne assignments, to Belmont Radio Corporation, Chicago, Ill., acorporation of Illinois Application April 24, 1944, SerialNo. 532,443

27 Claims. (01. 74-10) The present invention relates to control devicesand more particularly to improved control apparatus for selectivelytuning a radio receiver to desired signal channels.

Various push button actuated mechanically controlled devices arecommercially available for selectively actuating the tuning elements ofa radio receiver to settings corresponding to particular desiredstations. An improved device particularly adapted for this use isdisclosed in United States Letters Patent No. 2,243,487, granted May 27,1941, to the present applicant. This device employs a rotatable tuningshaft having a plurality of heart-shaped cams or control elements spacedaxially therealong, which are adapted to be engaged by cam rollersrotatably carried by movable push button actuated manuals arrangedtransversely of the tuning shaft, the arrangement being such that whenany manual is actuated, the associated cam roller and control elementare engaged to move the tuning shaft to a setting corresponding to apredetermined signal channel. At one end of the tuning shaft, facilitiesincluding a manually operable second shaft extending normal to thetuning shaft through the escutcheon plate of the receiver, areprovidedfor the purpose of manually rotating the tuning shaft to stationreceiving settings other than those to which the tuning shaft may beoperated by the manuals, and for the additional purpose of releasablyexerting a clamping force upon the control elements axially of thetuning shaft to permit adjustment of each control element relative tothe tuning shaft. Such adjustment is necessary in order accurately toposition the control elements for the operation of the tuning shaft tothe settings which exactly correspond to the desired signal channels.Releasable clamping arrangements .are also described in each of thefollowing Letters Patent of the United States: Morin No. 1,828,197,granted Oct. 20, 1931; Morin No. 1,906,709, granted May 2, 1933; GerschNo. 2,153,865, granted April 11, 1939; Benton No. 2,200,211, granted May7, 1940; Wells No. 2,214,785, granted Sept. 17, 1940; and Marholz etal., No. 2,330,833, Oct. 5, 1943.

In the specific improved embodiments of these facilities disclosed inthe above mentioned Plensler patent, the second shaft is movable axiallybetween a position wherein it is connected to drive the tuning shaft anda position wherein it is connected to drive a, traveling nut axially ofthe tuning shaft to tighten or relieve the clamping force restrainingthe control elements against movement relative to the tuning shaft.

Functionally, this arrangement has the disadvantage that four unusedaxial movements of the second shaft are required in each control elementresetting operation. This is due partially to the fact that each timethe second shaft is moved to a position for rotating the traveling nutthe tuning shaft drive connection is broken.

It is an object of the present invention, therefore, to provide improvedmanual tuning and control element locking facilities of the characterdescribed wherein only two axial actuations of the manually operablesecond shaft are required in a complete control element resettingoperation.

According to another object of the invention, the improved manual tuningand control element locking facilities are so arranged that each axialmovement of the manually operable second shaft is positively used eitherto clamp or unclamp the control elements, thereby to prevent or permitadjustment of these elements relative to the tuning shaft.

In accordance with a further object of the invention, the clamping andunclamping of the control elements is accomplished without breaking thedriving connection between the manually operable second shaft and thetuning shaft.

More generally stated, it is an object of the present invention toprovide in a control device of the character described, improvedfacilities for releasably locking the control elements against movementrelative to the tuning shaft, which' facilities are of sturdy and cheapconstruction, and may be easily actuated either to release the controlelements for movement relative to the tuning shaft or to positively lockthese elements against movement relative to the shaft.

It is a still further and more specific object of the invention toprovide an improved rack and pinion assembly for releasably locking thecontrol element of a control device against movement relative to acontrol shaft, which assembly is operated to lock and release thecontrol elements in response to longitudinal movement of the rackstransversely of the control shaft.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the specification taken in connection withthe accompanying drawings, in

which:

Fig. 1 is a side view, partially in section, illustrating improvedcontrol apparatus characterized by the features of the presentinvention;

Fig. 2 is an under-side view, partially in section, of the apparatusshown in Fig. 1;

Fig. 3 is an end sectional view taken along the lines 3-3 in Fig. 2,illustrating the construction and arrangement of the control elementsand associated manuals;

Fig. 4 is an end view of the apparatus shown in Fig. 2, with certain ofthe parts thereof broken away to facilitate an understanding of themech: anism for manually adjusting the tuning shaft and for releasablylocking the control elements against adjustment relative to this shaft;

Figure 5 is a view taken on line 5-5 of Fig. 2;

Fig. 6 is a detail sectional view taken along the lines 6-6 in Fi 5;

Fig. 7 is a fragmentary view, partially in section, illustrating amodified arrangement of the control apparatus and more particularly themanual tuning and control element locking facilities provided therein;

Fig. 8 is an end view partially in section of the apparatus shown in Fi7; and

Figs. 9, 10, 11, 12 and 13 are detail views illustrating certain of theparts embodied in the apparatus shown in Figs. '7 and 8.

Referring now to the drawings, and more particularly to- Figs. 1 through6 thereof, the present improved control apparatus is there illustratedin its embodiment in a radio receiver for the purpose of adjusting thegang connected frequency changing elements which are utilized in awell-known manner to tune the receiver to different signal channels, i.e., to tune the receiver for the reception of signals radiated atdifferent carrier frequencies. More specifically, the frequency changingmeans of the receiver comprises a pair of tuning condensers l carried bya fixed U-shaped supporting frame l3, and having a rotatable shaft IIwhich carries the rotor plates of the condenser and may be rotatablethrough 180 to provide the full tuning range for the receiver. Thesecondensers are electrically included in the receiver circuit in anyconventional manner, and the supporting frame l3 therefor is mountedupon the frame l2 of the control or tuning apparatus at one end of thisapparatus. The rotor shaft II is suitably journaled within bearingscarried by the legs of the U-shaped frame member I3 and the parallelextending side parts I21; and l2c of the frame member I2.

The control or tuning shaft II also carries a plurality of control ortuning selector elements 14 in the form of heart-shaped cams which arespaced axially along the shaft at the correct points for engagement bycam rollers l 'rotatably supported upon pivotally mounted manuals I5. Asbest shown in Fig. 3 of the drawings, each manual I5 is in the form of alever,-is pivotally mounted at one end upon a pivot shaft l1, carries acam actuating roller H5 at its opposite end, and

is provided with a manually operable push button I!) extending outwardat an angle from one edge thereof. The shaft or pivot rod I1 issupported at its ends by the side parts l2b and I20 of the frame l2, andcarries spacing sleeves l8 intermediate the levers l5 for the purpose ofmain-. taining the rollers H3 in transverse alignment with theirrespective associated cams ll. A second supporting plate 25 is providedat the back side of the longitudinally extending frame part l2a, this.

supporting plate being provided with a stamped out bumper part 25a, theouter edge of which is disposed in the paths of rotation of the adjacentlever ends. Single turn coil springs 9 wrapped around the pivot shaft H,are utilized to bias the levers l5 into engagement with the bumper part25a. Thus, and as best shown in Fig. 3 of the drawings, a springindividual to the lever l5c is provided for normally biasing this leveragainst the bumper part 25a so that the roller l6c is out of the path ofrotation of the associated cam Ilc. One end of this spring is anchoredto the extreme right end of the lever I50 and the opposite end thereofis held against unwinding movement through its engagement with the edgeof the bumper part 25 Similar springs 9, individual to the other leversl5, and spaced along the pivot shaft H are utilized normally to bias theother levers to engage the bumper part 25a.

The control elements [4 are maintained in spaced-apart relationshipaxially of the tuning shaft H by means of spacing sleeves 20 andfriction washers 2|, keyed or otherwise locked to shaft II, the latterelements being utilized to restrain the control elements l4 againstmovement relative to the shaft II when a clamping pressure of suitablemagnitude is exerted axially of the shaft upon the stacked elements I4,20 and H in the manner explained below. More specifically, theidentified elements are adapted to be clamped by means of thecombination manual tuning and control element locking mechanism which issupported upon the frame l2c to the outside thereof, against the end ofa sleeve 20a fixedly secured to the shaft II.

All parts of this mechanism are either carried directly by the shaft Hat the right end thereof as viewed in Figs. 1 and 2 of the drawings, orupon the legs 26a and 26b of a pair of L-shaped brackets 26, which arerigidly mounted upon the frame part He by means of mounting screws 21.Briefly considered, the manual tuning facilities of this mechanismcomprise a. carriage member 30, slidably supported at the leg ends ofthe two L-brackets 26; an L-shaped supporting member 3| supported bymeans of bolts or rivets 32 for limited sliding movement relative to thecarriage member 30; a manually operable shaft 50 extending normal to thetuning shaft II and journaled for rotation in a bearing member 5|fixedly mounted at the end 3la of the supporting member 31; a longpinion or gear 49 mounted upon the shaft 50 for rotation therewith; anda crown gear 48 fixedly mounted upon the tuning shaft II at the rightend thereof and having teeth meshing with the teeth of the pinion gear49 at all positions of the shaft 50 axially of the tuning shaft II. Itwill be understood that the push buttons l9 and the shaft 50 are adaptedto extend through openings in the escutcheon plate of the receiver formanual actuation from outside of the receiver housing. To facilitatemanual rotation of the shaft 50, a knob 53 is mounted upon theprojecting end thereof by means of a set screw 54. This shaft and theparts carried therebyare restrained against longitudinal movementrelativeto the supporting member 3| and the bearing 5| by means of thelong pinion 49 and a locking collar 52 which is set screw mounted uponthe shaft 50 adjacent the end of the bearing member 5|. With thisarrangement, the tuning shaft l l and the various parts carried therebymay be rotated to any desired setting within the limits of the tuningrange by appropriate finger manipulation of the knob 53 to rotate theshaft 50 in the desiredv direction. Thus when this shaft is rotated ineither direction, the tuning shaft ll and the parts carried thereby arerotated in a corresponding direction through the driving connectionafforded by the meshing, engagement of the long pinion 49 with the teethof the crown gear 48.

As indicated above, the facilities for releasably looking or clampingthe control elements |4 against rotary movement relative to the tuningshaft II are operated in response to longitudinal movement of the shaft5|) transversely of the tuning shaft without breaking the drivingconnection between the two identified shafts. In brief, thesefacilitiesinclude two relatively rotatable pinions 28 and 29 which arerotatably supported by the tuning shaft intermediate the control elementl4 and the crown gear 48; and a pair of rack bars 34 and 35 which arepivotally mounted by means of pivot pins 36 and 31 upon opposite sidesof the carriage member 38 and are provided with teeth 43 and 44 normallydisengaged from the teeth of the pinion gears 28 and 29 but adapted forengagement with the pinion gear teeth when the carriage member 30 ismoved transversely of the tuning shaft I I by pulling the shaft 50outwardly from the escutcheon plate of the receiver. In order to effectmovement of the pinion 28 axially to the left as viewed in Fig. 2,of thedrawings during relative rotary'movement of the two pinions 28 and 29 inone direction, thereby to exert the desired clamping pressure upon thecontrol elements H, the two pinions 28 and 29 are provided with opposedhub portions having meshing cam teeth 28a and. 29a, respectively, at theengaging ends thereof. These teeth are provided with flatted endsdisposed in planes normal to the tuning shaft II, which ends aremaintained in engagement when the two pinions'are rotated to settingswherein the control elements |4 are clamped against rotation relative tothe tuning shaft At the left side thereof the pinion 28 is provided witha hub 28b for exerting the required clamping pressure upon the controlele-' ments |4 through a pair of sleeves 20b and 2|c. In order tomaintain a slight clamping pressure upon these control elements when thepinions 28 and 29 are rotated to release these elements for adjustmentrelative-to the shaft II, a dished spring washer 2|d is provided betweenthe two friction washers 2| a and 2|b.

More specifically to consider the mounting arrangement for the carriagemember 30 and the parts supported thereon, it will be noted from afrisideration of Figs. 4 and 5 of the drawings. th if this :member isprovided with a central rec- 'tangular slot 45 which is in longitudinalalignment with the shaft 50 and the edges of which are disposed withininterfitting slots Mia and 46b provided along the opposite side edges ofthe two L-brackets 26. The end of the tuning shaft I projects throughthe slot 45 to support the crown gear 48 in the manner explained above.Limited sliding movement of the supporting member 3| relative to thecarriage member 38 in a direction extending longitudinally of the shaft50 isobtained by extending the mounting rivets 32- through shortelongated slots 33 in the supporting member 3|. With this arrangement,the

pends of the slots 33 act as stops, to define the extent of relativesliding movement between the two members 30 and 3|. This relativemovement is utilized to move the toothed ends of the two yrack bars 34and 35 toward and away from each other during movement of the carriagemember 30 in directions to disengage and engage the rack 4 bar teethwith the teethof the two pinions 28 and 29. To this end, cam pins 38 and49 are I extends through an enlarged opening 40a in the carriage member30 and bears against the camming edge 42a of the camming ear 42. Thecamming pin 39, on the other hand, extends directly outward from therack bar 34 and engages the camming edge 4|a of the camming ear 4|. Forthe purpose of normally maintaining the pins 39 and 48 in engagementwith the camming edges of the two ears 4| and 42. the downwardlyextending ends of these two bars are interconnected by means of atension spring 41. Thus the bars are biased in a direction to move thetoothed ends thereof away from each other and away from the teeth of thepinions 29 and 28.

From the above explanation it will be understood that normally thecarriage member 30 and the parts supported thereon occupy the positions-illustrated in Fig. 5 of the drawings, that the teeth 43 and 44 of thetwo rack bars are disengaged from the pinions 29 and 28, and that thesetwo pinions occupy the relative angular settings illustrated in Fig. 1of the drawings such that the control elements M are clamped or lockedagainst rotation relative to the tuning shaft II. It will be understoodalso that the control elements occupy different angular positionsrelative to the tuning shaft H such that the tuning condensers l0 may beoperated to signal channel settings respectively corresponding to thedifferent control elements through the selective manipulation of thepush buttons l9. It, with the apparatus in the condition just described,it is desired to tune the receiver for the reception of theparticularsignal correspondin to the push button I90, for example, this button maybe pushed downwardly from the position illustrated in Fig. 3 of thedrawings to bring the cam roller |5c into engagementwith the cammingsurface of the control element |4c.

During continued movement of the parts I90, I60 and |5c toward thetuning shaft H, the engaged roller |6c and control element |4c coact torotate the tuning shaft II to the particular angular settingcorresponding to the desired signal channel. This tuning position of theshaft is reached when the roller |6c is moved to engage the low point ofthe cam |4c. After it is reached, the push button |9c may obviously bereleased to return to its normal position under the influence of thebiasing spring 90. In a manner entirely similar to that just described,the other push buttons I9 may be selectively actuated for the purpose ofselectively tuning the receiver to the other signals to which thesepushbuttons respectively correspond. Tuning of the receiver to a'signalwithin the signal reception band of the receiver, but not correspondingto one of the push buttons I9, is accomplished through manual actuationof the knob 53 in the manner explained above.

As previously indicated, in order to adjust the angular settings of thecontrol elements |4 relative to the tuning shaft thereby to change thesignal channels to which these elements are respectively capableoftuning the receiver, the clamping pressure exerted axially of the shaftupon the control elements I4 is partially released.

To this end, the knob 53 is pulled outwardly from the escutcheon plateof the receiver, thereby to move the carriage member 30 and the partscarried thereby transversely of the tuning shaft H in a direction torotate the pinions 28 and 29 so that the cam teeth 43 and 44 thereof arebrought into full meshing engagement. Throughout such transversemovement of the carriage member 30, the long pinion 49 is obviouslymaintained in meshing engagement with the crown gear 48. During theinitial outward movement of the knob 53 and the parts 50, 49 and. 3|,the carriage member 30 remains stationary, due to the pin and slotconnection between the two parts 39 and 3|. Incident to this relativemovement between the identified parts of 30 and 3 the cam ears 4| and 42are withdrawn from the pins 39 and'40 permitting the rack teeth 43 and44 to move away from each other under the influence of the spring 41.The purpose of this limited pivotal movement of the rack bars 34 and 35during the initial pulling movement on the knob 53 is to prevent theleading teeth of the two rack bars from lockingly engaging displacedteeth of the two pinions 28 and 29 and to insure the same pinion toothdisplacement between the leading teeth of the two rack bars duringsuccessive operations of the carriage member 30 to release the clampingpressure from the control elements M. In this' regard it will beunderstood that should the leading rack bar tooth 43a, for

, example, engage the end of the tooth 29b and the leading tooth of therack bar 35 engage the end of a similarly positioned tooth on the pinion28,v

with no facilities for pivotal movement of the two rack bars 34 and 35,a lockin connection would be set up between the two rack bars 34 and 35through the pinions 28 and 29 and the shaft H which would positivelyprevent further transverse movement of the carriage member 30 and partscarried thereby. The limited pivotal movement of the two bars 34 and 35permits the leading teeth of the rack bars to ride over or not engagethe ends of the wrong pinion teeth and insures the same pinion toothdisplacement between. the leading rack barteeth during successivetransverse movements of the carriage member 39 to the control elementrelease position.

After the lost motion between the two parts 39 and 3| has been taken upin the manner just explained, the carriage member 39 and the two rackbars 34 and 35 are moved with the parts 3| and 59 during the continuedmovement of the parts outwardly from the shaft Accordingly, the teeth 43and 44 are moved into meshing engagement with the teeth of the pinions29 and 29, following which these pinions are rotated relative to eachother in the proper directions to bring the cam teeth 28a and 29a intofull meshing engagement. As these cam teeth are brought into mesh, thespring washer 2 Id acts to move the pinion 28 along the shaft to theright as viewed in Figs. 1 and 2 of the drawings, thereby to relieve theclamping pressure exerted upon the control elements |4 axially of theshaft'through the spacing sleeves 20. Thus the control elements H arere- Y leased for adjustment relative to the shaft Following theoperations just described, the control element l'4a, for example, may beset to a new angular position relative to the shaft so that it willcoact with the manual I90, and its associated parts to tune the receiverfor the reception of a different desired signal. To this end, the knob53 is first used to manually tune the receiver to the desired signalfrequency. After the 8 desired signal has thus been selected, the knob53 is held against further rotation, and the manual |9a is actuated forthe purpose of rotating the control element I 442 to the new settingrelative to the shaft After the new setting is thus established, themanual |9a may be released. In a manner entirely similar to that justdescribed, any one or all of the remaining five control elements may beset to new positions relative to the shaft II. In this regard, it ispointed out that the spring washer 2I'd maintains sufficient axialpressure upon the control elements to prevent the same from beingrotated relative to the friction washers 2| keyed to the shaft Iotherwise than in the manner just described. In other words, the spring2|d prevents'the desired angular settings of the control elementsrelative to the shaft H.

from being disturbed when once established.

After all of the control elements have been adjusted in the mannerexplained above, they may be relocked against movement relative to theshaft II by pushing upon the knob 53 to move the carriage member 39 andthe parts carried-thereby back to their respective normal positions.During the initial backward movement of the supporting member 3|, thecarriage member 30 remains stationary and the cam ears 4| and 42 coactwith the cam pins 39 and 49 to rotate the toothed ends of the rack bars34 and 35 toward each other, thereby to move the teeth 43 and 44 intodeeper meshing engagement with the teeth of the pinions 29 and 29. Afterthe lost motion between the two members 3| and 30 is taken up, these twomembers move in unison, thereby reversely to rotate the two pinions 28and 29 relative to each other until the cam teeth respectively carriedthereby are engaged only at their fiatted ends in the manner shown inFig. 1 of the drawings. Incident to the described relative movement ofthe cam teeth 28a and 29a, the

pinion 28 is moved axially to the left to flatten the springwasher 2|dand thus increase the clamping pressure exerted upon the controlelements |4 sufliciently to lock these elements against rotationrelative to the shaft During the final movement of the carriage member3|! and its associated parts back to their respective normal positions,the teeth 43 and 44 of the rack bars 34 and 35 are disengaged from theteeth of the pinions 29 and 28, thereby to free the tuning Y pinions 29and 29. This arrangement is to be distinguished from conventionallocking mechanism wherein the tuning shaft must be rotated to a stopposition at one end of the tuning range before the looking or clampingmechanism can be actuated to release the control elements foradjustmentrelative to the tuning shaft, and the tuning shaftmust be rotated to theopposite stop position at the other end of the tuning range before thelocking or clamping mechanism can be actuated to reclamp or relock thecontrol elements against movement relative to the tuning shaft. It willalso be noted that in the improved mechanism described above, eachmovemengtof the second shaft 50 is positively utilized to perform adefinite function, In other words, unnecessary movements of this shaftare entirely eliminated in the operation of the mechanism to perform thefunctions assigned thereto.

These same operating characteristics are also embodied in the modifiedarrangement illustrated in Figs. 7. through 13 of the drawings,whereinlike reference numerals have been used to identify correspondingparts. In a functional sense, the modified mechanism is the exactequivalent of that illustrated in Figs. 1 through 6 of the drawings anddescribed above. Structurally, however, the modified arrangementillustrated in Figs. 7 through 13 of the drawings is substantiallydifferent from the first described structure. More in detail, thesupporting bracket 26 of the modified structure is provided with fourequi-. angularly spaced legs which respectively terminate in outwardlyextending supporting parts 260, Ne, 26g and 26h, these parts beinglocated at different distances from the base of the bracket 26 in orderto provide for the required spacing of the rack bars 34 and 35 axiallyof the shaft I I in alignment with the teeth of the pinions 29 and 28.This bracket slidably supports the supporting member 3| which includesstepped but parallel extending legs 3|c and 3|d slidably engaging theparts 269 and 26h of the bracket 26. The two leg parts 3|c and 3|d arerespectively slotted at 3|e and 3|! to receive headed assembly rivets orscrews 32a and 32b, which are rigidly mounted within openings throughthe bracket parts 269 and 26h. The slidable support for the member3|.also comprises a part 3|b which projects from the member 3| and isslotted along the opposite edges thereof as indicated at 3|g to interfitwith the edges of a channel 26d cut in the bracket part 260. Thus athree-point sliding support is provided for mounting the supportingmember 3| upon the bracket 26 for movement transversely of the tuningshaft The rack bars 34 and 35 are of L-shaped configuration, beingpivotally and slidably supported at their base leg ends upon the steppedpart 26a of the bracket 26. More specifically, the base legs of the tworack bars are disposed upon opposite sides of the bracket part 26e andare pivotally'interconnected at their ends by means of a pivot pin 68which is slidable within a slot 26 cut in the identified bracket part.Rubber friction washers 6| disposed upon opposite sides of the bracketpart 26c and carried by the pivot pin 68 are utilized to space the rackbars apart the required distance to align the teeth 43 and 44 thereofwith the pinions 29 and 28, Lost, motion means are utilized tointerconnect the opposite ends of the rack bars 34 and 35 with the legs,3|c and 3|d of the supporting member 3|. More specifically, pins 62a and62b are respectively mounted upon the two legs 3id and 3|c to coact withangularly extending slots 63a and. 63b in the rack bars 34 and 35 forthe purpose of moving the teeth of these bars toward and away from eachother during movement of the supporting member 3| transversely of thetuning shaft II. The rubber friction washers 6| supply the requiredfrictional drag to resist movement of the rack bars transversely of theshaft H and thus insure operation of the camming means to move thetoothed ends of the bars toward and away from each other during movementof the carriage means transversely of the shaft. Thus, the pin and slotconnections 62 and 63 perform the same function in the mechanismdisclosed in Figs. 7 and 8 as do the cam ears 4| and 42, and pins 39transversely of the tuning shaft and 40 in the mechanism shown in Figs.1 through 6, inclusive.

The manually operable second shaft 50 of the mechanism shown in Figs. 7and 8 is provided with an end portion of reduced diameter which isJournaled in a bearing sleeve 5| rigidly mounted within an openingthrough a supporting panel 64. This panel is in turn rigidly mountedupon the supporting member 3|. At its inner end, the shaft 50 carriesthe long pinion 49 which meshes with the crown gear 48 to provide adriving connection between the two shafts 50 and II at all positions ofthe supporting member 3| The pinions 28 and 29 are provided with axiallydisposed cam. teeth 28a and 29a for supplying the required axial thrustupon the spacing sleeves 20 and friction washers 2| to restrain thecontrol elements |4 against rotary movement relative to the shaft ll,Here again, the ends of the teeth 28a and 29a are flattened so thatrelative movement between the two pinions is prevented when thesepinions occupy positions wherein the control elements H are clampedagainst rotation relative to the shaft The shaft H is threaded at theend upon which the crown gear 48 is mounted, in 'order to receive a nut65 which is utilized to fix the initial positions of the pinions 28 and29 along the shaft The thrust normally exerted upon the control elementsl4 through the sleeves 20 and the washers 2| is thus determined by thesetting of the nut 65 along the shaft H, and may obviously be adjustedas de-'- sired by setting the nut 65 at different positions axiallyalong this shaft. Once the desired nut position is established, thecrown gear 48 is set screw mounted upon the projecting end portion ofthe shaft, thereby to prevent inadvertent travel of the nut 65 towardthe shaft end.

As indicated above, the modified mechanism just described isfunctionally equivalent to the first embodiment of the invention asdisclosed in Figs. 1 to 6, inclusive, of the drawings. In this regard,it will be understood that with the parts of the modified mechanismccupying the positions illustrated in Figs. 7 and 8 of the drawings, theknob 53 may be rotated at will for the purpose of actuating the shaft IIto any desired tuning position. It will be understood further, that whenthe knob 53 is pulled outwardly from the shaft II, the supporting member3| and the rack bars 34 and 35 are moved transversely of the shaftcausing the teeth of the rack bars to engage the pinions 28 and 29 torotate these pinions relative to each other until the cam teeth 28a and2911 are in full meshing engagement, thereby to release the axial thrustholding the control elements against adjustment relative to the shaftWhen these elements have been set in the desired adjusted positionsrelative to the shaft H, the knob 53 may be pushed inwardly causing therack bars 34 and 35 to reversely rotate the pinions for the purpose ofre-establishing the clamping pressure upon the control elements, Duringthe forward movement of the member 3| relative to the support bracket 26the pins 62a. and 62b coact with the cam slots 63a and 63b to move thevrack bar teeth 43 and 44 away from the shaft thereby to. prevent theestablishment of a binding or looking connection which might prevent.meshing engagement of the teeth with the pinion teeth, and to insure thesame pinion tooth displacement between the leading rack bar teeth duringsuccessive engagements of these teeth with the pinions. Converse-.

ly, during backward movement of the member 3| transversely of the shaftH, the pins 62a. and. 62b coact with the slots 63aand 63b to producefull meshing engagement of the rack bar teeth 43 and 44 with the engagedpinion teeth, thereby to insure the required relative rotation of thepinions 28 and 29 to move these pinions back to the relative positionsillustrated in Fig. 7 of the drawings.

While two embodiments of the invention have been disclosed, it will beunderstood that various modifications may be made therein withoutdeparting from the spirit and scope of the invention as defined in theappended claims.

I claim:

1. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft and releasably restrained againstmovement relative to said shaft; a manually operable element, meanssupporting said element for two characteristic types of movement, meansfor rotating said shaft to any setting within said range in response toa corresponding movement of said manually operable element of one ofsaid types, and means responsive to movement of said manuall operableelement of the other of said types for releasing said selector elementsfor movement relative to said shaft.

2. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range between predetermined stop settings and.ments for movement relative to said tuning shaft.

3. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tun-' ing range between predetermined stop settingsand a plurality of tuning selector elements carried by said shaft andreleasably restrained against movement relative to said shaft; amanually operable shaft, means supporting said manually operable shaftfor rotary and axial movement, means responsive to rotation of saidmanually'operable shaft for rotating said tuning shaft to differentsettings within said tuning range, and means operative in response tomovement of said manually operable shaft axially in one direction forreleasing said elements for movement relative to said tuning shaft andoperative in response to movement of said manually operable elementaxially in the reverse direction for again restraining said selectorelements against movement relative to said shaft.

4, In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft and releasably restrained againstmovement relative to said shaft; a manuall operable element, meanssupporting said element for two characteristic types of movement, meansinterconnecting said shaft and said manually operable element to providea driving connection for rotating said shaft to different settingswithin said range in response to movement of said manually operableelement of one of said types, and means responsive to movement 12 ofsaid manually operable element of the other of said types for releasingsaid selector elements for movement relative to said shaft withoutbreaking the driving connection between said manually operable elementand said shaft.

5. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft and releasably restrained againstmovement relative to said shaft; a second shaft, means supporting saidsecond shaft for rotary and axial movement, interengaged and relativelymovable driving parts interconnecting said shafts to rotate said tuningshaft to different settings within said range in response to rotation ofsaid second shaft, and means responsive to axial movement of said secondshaft for releasing said selector elements for movement relative to saidshaft without disengaging said relatively movable parts to break thedriving connection between said shafts.

6. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft and releasably restrained againstmovement relative to said shaft; a second shaft, means supporting saidsecond shaft for rotary and axial movement, interengaged and relativelymovable driving parts interconnecting said shafts at allaxial settingsof said second shaft to provide a connection for rotating said tuningshaft in response to rotation of said second shaft, and restrainingmeans controlled by 'axial movement of said second shaft for releasablyrestraining said tuning shaft and said selector elements againstrelative movement.

7. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft; a second shaft disposed at an anglerelative to said tuning shaft, means S pp rt said second shaft forrotary and axial movement, a crown gear fixedly mounted upon said tuningshaft, an elongated pinion fixedly mounted upon said second shaft andmeshing with said crown gear in all axial settings of said second shaft,whereby said tuning shaft may be rotated to different settings withinsaid tuning range by rotating said second shaft regardless of the axialsetting of said second shaft, and restraining means controlled by axialmovement of said second shaft for releasably restraining said tuningshaft and said selector elements against relative movement.

8. In radio 'tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft, a carriage movable transversely of saidshaft, a second shaft rotatably supported by said carriage, interengagedand relatively movable driving parts interconnecting said shafts at alltransverse settings of said carriage to provide a connection forrotating said tuning shaft in response to rotation of said second shaft,interengageable parts respectively supported by said carriage and saidtuning shaft for movement into and out of engagement in response tomovement of said carriage transversely of said tuning shaft, and meanscontrolled by movement of said last-named parts when engage-d forreleasably restraining said tuning shaft and said selector elementsagainst relative movement.

9. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning I range and a plurality of tuning selectorelements shaft and said selector elements against relative movement, andrack means carried by said carriage and engageable with said pinions tomove said cam means between selector element release and selectorelement restraining settin s in response to movement of said carriagetransversely of saidtuning shaft.

10. In radio tuning apparatus which includes a tuning shaft rotatablethrough a desired tuning range and a plurality of tuning selectorelements carried by said shaft, a carriage. movable transversely of saidshaft, a second shaft rotatably supported by said carriage, interengagedand relatively movable driving parts interconnecting said shafts at allsettings of said carriage to provide a connection for rotating saidtuning shaft in response to rotation of said second shaft, a pair ofpinions supported upon said tuning shaft for relative rotary movement,cam means controlled by relative rotary movement between said pinionsfor releasably restraining said tuning shaft and said selector elementsagainst relative movement, a pair of rack bars pivotally supported bysaid carriage and respectively engageable with said pinions uponopposite sides of said. tuning shaft to move said cam means betweenselector element release and selector element restraining settings inresponse to movement of said carriage transversely of said tuning shaft,and means coacting with said rack bars for insuring the same piniontooth displacement between the leading teeth of said rack bars and theteeth of said pinions during successive operations of said carriage toeffect the release of said selector elements.

11. In a control device which includes a plurality of control elementscarried by a rotatable shaft; cam. means rotatably supported by saidshaft to exert a restraining force upon said elements, said cam meansand said shaft being relatively rotatable between positions wherein saidelements and said shaft are relatively movable and'are restrainedagainst relative movement, carriage means movable transversely of saidshaft and including rack means operative to produce relative movementbetween said shaftand said cam means during such transverse movement,and means including an element rotatably supported by said carriagemeans for rotating said shaft and control elements in unison in at leastone.posi tion of said carriage means. 3 12. In a control device whichincludes a, plurality of control elements carried by a rotatable shaft;a pinion rotatably supported by said shaft, cam means rotatable withsaid pinion and operative to exert a restraining force upon said elements, said cam means being rotatable relative to said shaft by saidpinion between positions 14 pinion to rotate said pinion and cam meansrelative to said shaft during movement of said carriage meanstransversely of said shaft, and means including an element rotatablysupported by said carriage'means for rotating said shaft and controlelements in unison in all positions of said carriage means transverselyof said shaft.

13. In a control device which includes a plurality of control elementscarried by a rotatable shaft; a pinion rotatably supported by saidshaft, cam means rotatable with said pinion and operative to exert arestraining force upon said elements, said cam means being rotatablerelative to said shaft by said pinion between positions wherein saidelements and said shaft are relatively movable and are restrainedagainst relative movement, carriage means movable transversely of saidshaft, a rack bar pivotally supported by said carriage means andoperative to engage said pinion to rotate said pinion and cam meansrelative to said shaft .during movement of said carriage meanstransversely of said shaft, and means interconnecting said rack bar anda part of said carriage ,means for pivoting the toothed end of said rackbar away from said shaft before said rack bar and pinion are engaged. V

14. In a control device which includes a plurality of control elementscarried by a rotatable shaft; 9. pair of pinions rotatably supported bysaid shaft, cam means disposed between said pinions for actuation inresponse to relative rotation of said pinions and operative to exert arestraining force upon said elements, said cam means being movablebetween positions wherein said elements and said shaft are relativelymovable and are restrained against relative movement in response torelative rotation of said pin-- ions in reverse directions, carriagemeans movable transversely of said shaft, rack bars pivotally supportedby said carriage means and operative to engage said pinions uponopposite sidesof said wherein said elements and said shaft arerelatively movable and are restrained against relative movement,carriage means movable transversely of said shaft, a, rack bar pivotallysupported by said carriage means and operative to engage said shaft,thereby to produce relative rotation of said pinions in oppositedirections in response to reverse transverse movements of said carriagemeans, and means including an element rotatably supported by saidcarriage means for rotating said shaft and control elements in unison inall positions of said carriage means transversely of saidshaft.

15. In a control device which includes a plurality of control elementscarried by a rotatable shaft; a pair of pinions rotatably supported bysaid shaft, cam means disposed between said pinions for actuation inresponse to relative ro-, c

tation of. said pinions and operative to exert a restraining force uponsaid elements, said cam means being-movable between positions whereinsaid elements and said shaft are relatively movable and are restrainedagainst relative movement in response to relative rotation of saidpinions in reverse directions, carriage means movable transversely ofsaid shaft, rack bars pivotally supported by'said carriage means andoperative to engage said pinions upon opposite sides of said shaft,thereby to produce relative rotation of said pinions in oppositedirections in response to reverse transverse movements of said carriagemeans, and means interconnecting said rack bars and a part of saidcarriage means to permit limited relative movement between each of saidrack bars and said carriage means, thereby to prevent locking engagementbetween the leading teeth of said rack bars and the respectivecorresponding teeth of said pinions during the initial .ngagement ofsaid leading rack bar teeth with the corresponding teeth of saidpinions.

16. In a control device, a shaft, a pair of pinions rotatably supportedby said shaft, control means carried by said shaft, mechanism responsiveto relative rotary movement between said pinions for controlling saidcontrol means, carriage means movable transversely of said shaft, rackbars pivotally supported by said carriage means and operative to engagesaid pinions upon opposite sides of said shaft, thereby to producerelative rotation of said pinions in opposite directions in response toreverse transverse movements of said carriage means, and meansresponsive to each of successive movements of said carriage means in adirection to engage said rack bars and pinions for moving the leadingteeth of said rack bars away from each other before they are moved intomeshing engagement with the teeth of said pinions, thereby to preventlocking engagement between said leading teeth of said rack bars and therespective corresponding teeth of said pinions during the initialengagement of said leading rack bar teeth with the corresponding teethof said pinions. 17. In a control device, a shaft, a pair of pinionsrotatably supported by said shaft, control means carried by said shaft,mechanism responsive to relative rotary movement between said pinionsfor controlling said control means, carriage means movable transverselyof said shaft, rack bars pivotally supported by said carriage means andoperative to engage. said pinions upon opposite sides of said shaft,thereby to produce relative rotation of said pinions in oppositedirections in response to reverse transverse movements of said carriagemeans, and means responsive to each of successive back and forthmovements of said carriage means for moving the leading teeth of saidrack bars away from each other before they are moved to mesh with theteeth of said pinions each time said carriage means is moved in adirection to engage said rack bars and pinions and for moving saidleading teeth of said rack bars toward eachother during the reversemovement of said carriage means, thereby to prevent locking engagementbetween said leading teeth of said rack bars and the respectivecorresponding teeth of said pinions during the initial engagement ofsaid leading rack bar teeth with the teeth of said pinions and toprovide for the same pinion tooth displacement between said leading rackbar teeth during repeated engagement of said leading rack bar teeth withthe teeth of said pinions.

18. In a control device, a shaft, a pair of pinions rotatably supportedby said shaft, control means carried by said shaft, mechanism responsiveto relative rotary movement between said pinions for controlling saidcontrol means, carriage means movable transversely of said shaft andcomprising two relatively movable parts, rack bars pivotally supportedby one vpart of said carriage means and operative to engage said pinionsupon opposite sides of said shaft, thereby to produce relative rotationof said pinions in response to transverse movement of said carriagemeans, and camming means operative in response to the relative movementbetween said parts which occurs during transverse movement of saidcarriage means for moving the leading teeth of said rack bars away fromeach other before they are moved to mesh with the teeth of said pinions.

19. In a control device, a shaft, a pair of pinions rotatably supportedby said shaft, control means carried by said shaft, mechanism responsiveto relative rotary movement between said pinions for controlling saidcontrol means, carriage means movable transversely of said shaft andcomprising two relatively movable parts, rack bars pivotally supportedby one part of said carriage means and operative to engage said pinionsupon opposite sides of said shaft, thereby to produce relative rotationof said pinions in response to transverse movement of said carriagemeans, spring means tending to pivot the toothed portions of said rackbars away from each other, and camming means operative in response tothe relative movement of said carriage means for permitting the leadingteeth of said rack bars to move away from each other before they aremoved to mesh with the teeth of said pinions. 1 l

20. In a control device, a shaft, a pinion rotatably supported by saidshaft, control means carried by said shaft, mechanism responsive torelative rotary movement between said pinion and said shaft forcontrolling said control means, carriage means movable transversely ofsaid shaft, a rack bar pivotally supported by said carriage means andoperative to engage said pinion, thereby to produce relative rotationbetween said pinion and said shaft, in response to movement of saidcarriage means transversely of said shaft, and means responsive tomovement of at least a part of said carriage means in a direction toengage said rack and pinion for pivoting said rack bar relative to saidcarriage means in a direction to move the leading tooth of said rack baraway from said shaft as said rack bar teeth are moved into meshingengagement with said pinion.

21. In a control device, a shaft, a pinion rotatably supported by saidshaft, means carried by said shaft and controlled by relative rotarymovement between said pinion and said shaft, carriage means movabletransversely of said shaft and comprising two relatively movable parts,a rack bar pivotally supported by one part of said carriage means andoperative to engage said pinion during movement of said carriage meanstransversely of said shaft, thereby to produce relative rotation betweensaid pinion and said shaft, and means including camming means operativein response to the relative movement which occurs between said partsduring transverse movement of said carriage means for pivoting said rackbar to move the leading tooth of said rack bar away from said shaftbefore said rack bar teeth are moved into meshing engagement with saidpinion.

22. In a control device, a support, a shaft rotatably carried by saidsupport, a pair of pinions rotatably supported by said control shaft,means carried by said shaft and controlled by relative rotary movementbetween said pinions, rack bars movable transversely of said shaft anddisposed to engage said pinions upon opposite sides of said shaft,thereby to produce relative movement between said pinions when movedtransversely of said shaft, friction drag means slidably interconnectingsaid rack bars and said support, a member slidably carried by saidsupport to move said bars back and forth transversely of said shaft, andcam means interconnecting said bars and said member to move said rackbars apart as said member is moved to engage said bars and pinions V andto move said bars toward each other as said member is moved to disengagesaid bars and pinions.

23. In a control device which includes a plurality of control elementscarried by a shaft; the

means for releasably holding said elements in adjusted positions alongsaid shaft which comprises restraining means rotatably supported by saidshaft to exert a restraining force upon said elements, said restrainingmeans and said shaft being relatively rotatable between positionswherein said elements are movable relative to said shaft and arerestrained against movement relative to said shaft, and means includinga toothed member movable transversely of said shaft to engage saidrestraining means for producing relative movement of said shaft and saidrestraining means between said two positions.

24. In a control device which includes a plurality of control elementscarried by a shaft, a pair of pinions rotatably carried by said shaft,means normally restraining said elements against movement relative tosaid shaft and operative to release said elements for movement relativeto said shaft in response to relative rotation of said pinions, and rackbars engageable with said pinions upon opposite sides of said shaft andmovalble transversely of said shaft to engage said pinions and thenproduce relative rotary movement therebetween.

25. In a control device which includes a plurality of control elementscarried by a shaft, a pair of pinions rotatably carried by said shaft toexert an axially directed clamping pressure upon said elements, meansfor moving at least one of said pinions axially of said shaft to relievethe clamping pressure upon said elements in response to rotation of saidpinions relative to said shaft, and rack means engageable with saidpinions and movable transversely of said shaft to 18 engage said pinionsand then rotate said pinions about said shaft.

26. In a control device which includes a plurality of control elementscarried by said shaft, a pair of pinions rotatably carried by said shaftto exert an axially directed clamping pressure upon said elements, meansfor moving, at least one of said pinions axially of said shaft torelieve the clamping pressure upon said elements in response to oppositerotation of said pinions relative to said shaft, and rack barsengageable with said pinions upon opposite sides of said shaft andmovable transversely of said shaft to engage said pinions and thenproduce opposite rotation of said pinions about said shaft.

27. In a control device which includes a plurality of control elementscarried by said shaft, a pair of pinions rotatably carried by said shaftto exert an axially directed clamping pressure upon said elements, meansfor moving at least one of said pinions axially of said shaft to relievethe clamping pressure upon said elements in response to oppositerotation of said pinions relative to said shaft, a member movabletransversely of said shaft and provided with off set rack elementsoverlying said pinions upon opposite sides of said shaft, said rackelements including teeth engageable with said pinions upon movement ofsaid member transversely of said shaft, whereby said pinions areoppositely rotated to release said control elements for movementrelative to said shaft in response to movement of said membertransversely of said shaft.

ALEXANDER W. PLENSLER.

